Week 4- Statistics Chapter 4 Review Quiz

The table below shows the results of a customer survey on new home builders and whether they were within budget or over budget. What is the probability that a randomly chosen customer built their new home with Building Company B and it was within budget?

35/200

The table below shows the results of a customer survey of recent purchasers of certain brand of laptop computer. What is the probability that a randomly chosen customer is Very Dissatisfied?

39/500

The Stem-and-Leaf chart below represents the amounts spent in a store by 50 consecutive customers. What percentage of customers spent $60 or more?

4%

A company recorded the number of customer complaints received by its customer helpline on each of the last 30 working days and the stem and leaf plot of the data is shown below. On what percentage of days (to the nearest whole number) were there fewer than 20 complaints received?

43%

Mothers Against Drunk Driving is a very visible group whose main focus is to educate the public about the harm caused by drunk drivers. A study was recently done that emphasized the problem we all face with drinking and driving. Four hundred accidents that occurred on a Saturday night were analysed. Two items noted were the number of vehicles involved and whether alcohol played a role in the accident. The numbers are shown below: What proportion of accidents involved alcohol or a single vehicle?

Alcohol or 1 vehicle (or both): (50 + 25 + 100 + 20) / 400. The correct answer is: 195/400

With reference to the table above, which building company is most likely to be within budget?

B

Mothers Against Drunk Driving is a very visible group whose main focus is to educate the public about the harm caused by drunk drivers. A study was recently done that emphasized the problem we all face with drinking and driving. Four hundred accidents that occurred on a Saturday night were analysed. Two items noted were the number of vehicles involved and whether alcohol played a role in the accident. The numbers are shown below: Given that alcohol was not involved, what proportion of the accidents were single vehicle?

Conditional, 1 vehicle given no alcohol: 25 / 230. The correct answer is: 25/230

Events A and B are mutually exclusive. Following statements is true:

P(A or B) = P(A) + P(B)

A company has made available to its employees (without charge) extensive health club facilities that may be used before work, during the lunch hour, after work, and on weekends. In a random sample of 250 employees, 110 used the facilities at some time. Of the 170 males in the sample, 65 used the facilities. For a randomly-selected employee, calculate P[Uses facilities | Male] and P[Uses facilities | Female].

P[Uses facilities | Male] = 65/170 = 0.382 P[Uses facilities | Female] = 45/80 = 0.563

A company has made available to its employees (without charge) extensive health club facilities that may be used before work, during the lunch hour, after work, and on weekends. In a random sample of 250 employees, 110 used the facilities at some time. Of the 170 males in the sample, 65 used the facilities. Draw up a contingency table to represent this information.

Use Don't Use Total Male 65 105 170 Female 45 35 80 Total 110 140 250